At one time I thought they had some double face bar bumpers that went clear across, not bumperetts.
Both were available! The bumperetts were generally used if the vehicle had a rear mounted spare and the solid rear bumper was generally used if the car had sidemounts. However, since these were dealer installed accessories the dealer would install whatever the customer wanted. Therefore, a car with sidemounts could have the rear bumperetts.
The solid rear double face bar had a slightly different curve than the front double face bar because it is longer. Also, the rear bumper bracket was different than the front bumper bracket both in length and in curvature.